Table 2 lists the identified material parameters in the General Power-Law equation (Eq. (4)) and the corresponding R2 values. At each stress level, the initial creep compliance D0 decreased as the fiber content increased. The material parameter D1 has a similar varying trend as D0. Such behavior can be explained by the fact that
the addition of sisal fiber into the PE matrix decreases the compliance of the composites.
Fig. 2 demonstrates good agreement between the modeled and experimental creep curves in both the creep and creep-recovery regimes for all stress levels studied and various fiber contents. Therefore, we concluded that the General Power-Law equation could be used to model both the creep and creep-recovery behaviors of the composites being studied with sufficient accuracy.